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Re: Refastening Galv

Removing thousands of old rusted in place nails from the 1930's?
One at a time? Without causing big damage to the planking?

How about instead, removing the entire plank, can they be pried loose?
Repair this one plank at a time. But if you find rotten frames...
Or take a saw and cut all the nails between frame and plank so at least the planks are preserved. Perhaps you could core drill around the rusted nails in the framing, then glue in new wood plugs or dowels in the holes and refasten with bronze screws.

Re: Refastening Galv

Originally Posted by Peerie Maa

If they were pink and crumbley they were not bronze, no matter what you were told. That is classic dezincification of brass screws.

You know, I think I knew that but just assumed that the fasteners would have been bronze so never put it together. Not sure what brass fasteners were doing in the hull but you're right - they were pink and crumbly, so certainly dezincified brass.

Re: Refastening Galv

Originally Posted by Peerie Maa

If they were pink and crumbley they were not bronze, no matter what you were told. That is classic dezincification of brass screws.

My experience too.
Old genuine everdure bronze screws waste away without dezincing, because bronze is not supposed to have zinc. They still retain their strength even if the thread corrode away.
I have thousands of slightly wasted bronze screws I kept as they could be used again for maybe a row boat.

How can you tell brass from bronze screws?
It seems Egg Harbor used some larger brass screws above the waterline, they will break sometimes if reused, they twist off, and looking closely at snapped screws, the other layer is dezinced, but cant always see that before they break, I have seen them looking good and they are compromised. Nothing worse than driving in a screw and having it snap off in the wood.

Re: Refastening Galv

More words of wisdom --and having read of Perihelion, I give them great weight.

Bronze is not necessarily permanent.

Amen. After 30 years, enough of Bucephalus's bronze screws were pinkish-orange and nearly threadless (especially those *above* the waterline)(!?!) that I don't regret refastening. Granted, they were 1" #10s, so pretty small, but the principle stands.

That's a good trick, about using a bit of steel cable as a wire brush, and a good step-by-step tutorial in technique.

I expect I will be asking a lot of questions of Rob Abernethy during that boatbuilder's survey, including his recommendations of bronz vs. galv. As you say, the difference in cost is pretty trivial, especially when amortized over the next fifty years. If A&G do the work, going with what a boatbuilder knows and approves of often makes for a better, and sometimes even less expensive job. No one works well or expeditiously at something they don't believe in.

I hope to go have a look at the boat in about a week. At the moment I'm in an awful swivvet about whether this entire idea is a dud, but that's how it goes when all I can do is sit and think and imagine problems.

Re: Refastening Galv

Alex, I know next to nothing about refastening so I'll keep quiet about that. What I do have experience in is finding steel nails and screws in the walls of houses. There, rare earth magnets are your friend. The small ones, 1/8 x 3/8 inch will stick on the surface over any iron product within the wall or boat hull. Take a dozen or so with you for the inspection. They will easily reveal where the fasteners are without having to scrape paint and/or dig them out.

Re: Refastening Galv

Originally Posted by Pitsligo

More words of wisdom --and having read of Perihelion, I give them great weight.

Amen. After 30 years, enough of Bucephalus's bronze screws were pinkish-orange and nearly threadless (especially those *above* the waterline)(!?!) that I don't regret refastening. Granted, they were 1" #10s, so pretty small, but the principle stands.

That's a good trick, about using a bit of steel cable as a wire brush, and a good step-by-step tutorial in technique.

I expect I will be asking a lot of questions of Rob Abernethy during that boatbuilder's survey, including his recommendations of bronz vs. galv. As you say, the difference in cost is pretty trivial, especially when amortized over the next fifty years. If A&G do the work, going with what a boatbuilder knows and approves of often makes for a better, and sometimes even less expensive job. No one works well or expeditiously at something they don't believe in.

I hope to go have a look at the boat in about a week. At the moment I'm in an awful swivvet about whether this entire idea is a dud, but that's how it goes when all I can do is sit and think and imagine problems.

Alex

Alex, I suspect you have more than enough information and advice to make a decision on the refastening so I'll just leave off with this thought - I would love to be able to buy and live aboard an old Fisheries or Forestry patrol boat. Life being what it is that's not going to happen but I would at least like to live vicariously through others so if you do buy it please, please start a thread. With lots of photos!

Re: Refastening Galv

No finer vessels than the BC forestry boats.
After all this rank speculation, you've let us know that the fastenings are not bleeding, and that the boat generally seems to be in good shape. By all means have a proper survey.
Sounds like the shipwright you've mentioned feels replacement of existing fastenings at this time is relatively straightforward because they have not yet gone to hell. That's forward thinking. If the unnecessary expense of going bronze makes you feel better, than go for it. In the grand scheme, it is a fraction of the expense. There are reasonable arguments for bronze or galvanized. Easy for me, from afar, to lean towards galvanized in this case. We would love to hear more about what your guy says.

I was reminded recently by another Seattle shipwright that there is good galvanized and there is crappy galvanized, and it is not only a question of hot dipping. He was contemptuous of one supplier and much happier with another. I'm sorry I can't recall the names. If you go galvanized grill the yard about this - do they have an ironclad reliable source.
Eric

Re: Refastening Galv

Originally Posted by Eric Hvalsoe

I was reminded recently by another Seattle shipwright that there is good galvanized and there is crappy galvanized, and it is not only a question of hot dipping. He was contemptuous of one supplier and much happier with another. I'm sorry I can't recall the names. If you go galvanized grill the yard about this - do they have an ironclad reliable source.
Eric

This is a very, very good point. When we were doing the recent work on Petrel we had to buy a few screws from Tacoma Screw because we ran out of the good ones. They were of MUCH lower quality than the ones that Mark Lerdahl had been using. He gets his from Standard Fastenings (http://standardfastenings.com/). I think that may be where Admiral Ship Supply gets theirs as well.

Re: Refastening Galv

Skene's Elements of Yacht Design, chapter 11. Two pages long, including the table. Seems straightforward, has something changed since my copy was printed in 1973?

It seems to me that refastening planking on a galvanized bolted traditional carvel-planked boat with SB screws might create problems without removal of all existing plank fastenings. Accolade, red cedar planking on oak frames, was originally fastened in 1948 with galvanized boat nails, and these remain in combination with some galvanized screws, at least some of which come from a later refastening. While I mostly have been able to keep abreast of the existing bleeders from the original fasteners, and many of those nails still have a strenuous grip on their frame connection, I am glad that I am not having to keep up with the increased deterioration that might have resulted with a refastening with SB.

Re: Refastening Galv

Originally Posted by chas

Skene's Elements of Yacht Design, chapter 11. Two pages long, including the table. Seems straightforward, has something changed since my copy was printed in 1973?

It seems to me that refastening planking on a galvanized bolted traditional carvel-planked boat with SB screws might create problems without removal of all existing plank fastenings. Accolade, red cedar planking on oak frames, was originally fastened in 1948 with galvanized boat nails, and these remain in combination with some galvanized screws, at least some of which come from a later refastening. While I mostly have been able to keep abreast of the existing bleeders from the original fasteners, and many of those nails still have a strenuous grip on their frame connection, I am glad that I am not having to keep up with the increased deterioration that might have resulted with a refastening with SB.

...... or so it seems. / Jim

Ah now you would have me reaching for my copy of Skene's to figure out what you are talking about. Except I'm in Charlotte and my books are in Seattle. Argh!

Re: Refastening Galv

One of my Skene's (1948 6th Ed.) shows Chp XI is about Spars and Rigging; in the other (1962, w/ Kinney) XI is about... Propellors?

BUT...

I hear what you're saying, and I think I agree. Or, more to the point, I can't shake the entirely-unscientific intution that there'd be an unhappy interaction between the old iron residue and the new SB screws, and for the sake of caution and with the awareness that the new screws will probably last until I hand her off to her next vassal ...er, owner... left to my own devices I would just use galv.

Re: Refastening Galv

Galvanic Series of Metals - and a quote ..."You cannot use galvanized iron or steel next to bronze or Monel under salt water. They are too far apart on the list."

Couple of other rules in there that are relevant, regarding galvanic corrosion. What is the name of this boat you are looking at Alex? Somewhere there exists a website with a comprehensive listing of the BC Forestry boats and you might find some further info there. Best of luck in your upcoming decision. / Jim

Re: Refastening Galv

We took care of a wonderful Rhodes design 55' Yawl, built by Abeking and Rasmussen in 1950. We found a puzzling series of areas of the tight seams that were "erupting" for lack of a better word. When we withdrew some fasteners we found the bronze had turned pink, the same pink color we saw in bronze props. The areas were scattered, and there was no rhyme of reason to it, but it was obvious that electrolysis was to blame.
Then we looked deeper and found that these bad areas corresponded to the pattern of the diagonal bronze strapping the the designer spec' and the builder installed.
We replaced fasteners and also found that the active Electrolysis metering system had wasted reference zincs, I think we replaced the bronze sea cocks with the Forespar Marelon plastic ones as well.
I only mention it because it was a confusing repair. It is possible that the post WWII bronze was suspect, but fasteners away from the big bronze straps were fine.
If I was building a work boat for a client who needed 10-20 years of useful life, then galvanized screws would be just the ticket. If another client was specifying a gold plater with attendant nice systems and fixtures, then bronze would be the choice.
I have seen the galvanized fasteners removed from a Romsdal trawler built in the 60's as a yacht, and it was a shame to have disturbed them.
So many variables in coming up with a proper diagnosis and solution for a boat in your yard needing a repair solution.

Re: Refastening Galv

PhitsL, We have found over the years that the knee-jerk reaction to refasten Galv fastened boats with, in the in many ways superior bronze, sets in motion an accelerated wasting of the remaining existing fastenings, as well as seems to accelerate the wasting of the structural bolting which, on this boat will very likely be galvie drifts and bolts. So our first choice is always to stick with the metal chosen, for better or worse, by the builder. A close second for your situation, is high quality stainless, I have for 20 years owned a retired commercial boat ( a little Monterey Trawler, cedar on bent oak) that was built in '43 with galvanized boat nails, well before I bought her, she was refastened with larger stainless screws, leaving her old nails alone, to my surprise, this combination has withstood the test of time very well, with no incidences of crevice corrosion or the like discovered the in areas that we have repaired or replaced, or pulled for just for survey over the years.
I will second the earlier recommendation for Standard Fastenings, they are old school, and their product have always been top drawer, and they are the best source I know of for galvanized screws etc. Good luck! Steve

Re: Refastening Galv

Not that my tiny experience matters, but interesting enough I noticed the same outcome on Tonga (launched 1960). She's galvi-fastened, but there are several stainless screws from the same period, also below the waterline, which are still in perfect condition.

And by the way, thank you all very much for your interesting comments. Before this thread started I was still a bit unsure if sticking with galvi as opposed to SB is really a good idea, but you've convinced my now. I will re-fasten with galvi!

Re: Refastening Galv

Originally Posted by wizbang 13

diagonal bronze strap. now there is an idea whose time should have never come.

Well, Mr Herreshoff, Rhodes, Nielsen, etc, all spec'd bronze straps as part of their engineering to help larger sailing vessels hold their sheer line and reduce downward pressure on the mast steps. Some of these vessels have reached quite an age.

Re: Refastening Galv

Originally Posted by Paul Schweiss

Well, Mr Herreshoff, Rhodes, Nielsen, etc, all spec'd bronze straps as part of their engineering to help larger sailing vessels hold their sheer line and reduce downward pressure on the mast steps. Some of these vessels have reached quite an age.

Not to mention every composite clipper built as well as the big muti-masted schooners. Of course they used iron strapping. It was the only way to prevent a large wooden hull from hogging.

It really is quite difficult to build an ugly wooden boat.
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Re: Refastening Galv

I suspect that we have drifted Alex's thread right off the cliff at this point. So why not? I'll mention that I once saw a photo of a cold-molded ULDB that had an aluminum tube frame running the length of the boat to distribute the rigging loads. So the belt-and-suspenders approach isn't just for carvel boats. The epoxy crowd has had their day with it as well... I say this with no agenda other than to wind Bruce up a bit of course

Re: Refastening Galv

Re: Refastening Galv

We have found over the years that the knee-jerk reaction to refasten Galv fastened boats with, in the in many ways superior bronze, sets in motion an accelerated wasting of the remaining existing fastenings, as well as seems to accelerate the wasting of the structural bolting which, on this boat will very likely be galvie drifts and bolts. So our first choice is always to stick with the metal chosen, for better or worse, by the builder.

Boattruck, that answers *exactly* the concern I had when I started the thread. Thank you.

I suspect that we have drifted Alex's thread right off the cliff at this point.

Oh, Alex's thread has accomplished what Alex wanted, in ways Alex barely knew to hope for. Y'all have fun now. I'll keep my eye on the thread to see what comes of it, in case more info pops up, but at the moment I'm heading over to read more about Petrel.

Re: Refastening Galv

I bought cut thread galvanized screws from a couple different vendors to try them out. The 14's from Tacoma that I have used around the shop and in a few jigs were well galvanzied but I spun the heads off of a few. Quite concerning.

I'm not being flippant but I guess a screw is not just a screw. I'm guessing these are made overseas with lesser quality metallurgy?

Originally Posted by cstevens

This is a very, very good point. When we were doing the recent work on Petrel we had to buy a few screws from Tacoma Screw because we ran out of the good ones. They were of MUCH lower quality than the ones that Mark Lerdahl had been using. He gets his from Standard Fastenings (http://standardfastenings.com/). I think that may be where Admiral Ship Supply gets theirs as well.

Re: Refastening Galv

No, a screw is not just a screw. Even among the imports, there's wide variation in quality. One of the reasons I'm devoted to TopNotch Fasteners is that when I was refastening B, I bought a sub-box quantity of something I needed only a dozen of --4" #16s for the mast step, maybe?-- and of the dozen, five were clearly different from the other seven and completely unuseable. I called up Ron and he just sent me replacements, no questions asked.

Of the screws that were just fine, they *were* just fine, even though they were imports, but if those duds are common enough there's no wonder imports have a bad reputation.

As for Tacoma Screw, I never use their screws unless I can't avoid it. Poor quality, only square drive (no, we're not going to argue about drive preferences here!), and over priced. TopNotch doesn't sell galv, so on the recommendations of so many people here, I'll be setting up an account with Standard Fastenings.

Re: Refastening Galv

Originally Posted by scott2640

I bought cut thread galvanized screws from a couple different vendors to try them out. The 14's from Tacoma that I have used around the shop and in a few jigs were well galvanzied but I spun the heads off of a few. Quite concerning.

I'm not being flippant but I guess a screw is not just a screw. I'm guessing these are made overseas with lesser quality metallurgy?

As I understand it the heat then rapid cooling in manufacturing of some cut thread screws causes the metal to harden and become brittle at the thread to shank transition or just below the head and that causes the shearing off of heads.

Re: Refastening Galv

I can't comment on the metallurgy but the problem with the Tacoma Screw fasteners is at least partly that the shank is tapered at the transition.

(Tacoma screw fastener compared to a 25-yo screw that came with Petrel). They are very weak at that spot. I turned the heads off of a bunch of them when I was refastening the trunk cabin. I found this same issue in all the screws in several batches of different sizes over more than a year so it's not a case of a few bad ones. In the future I'll be ordering from Standard Fastenings or one of the other suppliers on Scott's list.